cairoShowGlyphs if the cairo
graphics state were set to the same font_face, font_matrix, ctm,
and font_options as scaled.font). Additionally, the x_advance and
y_advance values indicate the amount by which the current point
would be advanced by cairoShowGlyphs.cairoScaledFontGlyphExtents(scaled.font, glyphs, num.glyphs)glyphs list